a) Field of the Invention
This invention relates to a cleaning apparatus which washes deposits off the surface of a workpiece.
b) Description of the Related Art
When cutting metallic materials to be finished in a predetermined form, it is common that a cutting fluid is supplied to the workpiece surface between a metallic material and a cutting blade at all times to cool off the heat generated during cutting to increase the cutting performance. Then, the workpiece which has gone through the cutting process is sent to a cleaning apparatus, as illustrated in FIG. 3, to remove the cutting liquid or cutting waste deposited on the workpiece.
As illustrated in FIG. 3, the workpieces which went through the cutting process are held in a plurality of baskets (1) hanging on a conveyor (4) at almost an equal distance from each other. The conveyor (4) transports the plurality of baskets (1) while it repeats an up-down and a one-way operational movement at predetermined times. Under the conveyor (4), a cleaning apparatus (3) having a plurality of tanks (3a) to (3g) are installed. The cleaning apparatus (3) is comprised of a cleaning liquid tank (3a), rinsing tanks (3b) to (3e), and drying tanks (3f) to (3g) in that order along the movement of the conveyor (4). A cleaning liquid such as a mild detergent is held in a cleaning liquid tank (3a), which removes the lubricant liquid deposited on the workpieces (2). The workpieces (2), which are soaked into the cleaning liquid tank (3a) for a predetermined time, are sent to rinsing tanks (3b) to (3e) which are divided into several steps, each of which contains a rinsing liquid. The workpieces (2) which have gone through the rinsing tanks (3b) to (3e) are sent to drying tanks (3f) to (3g) which are arranged adjacent and where the rinsing liquid is heated for evaporation. The deposits on the workpieces (2) deposited during machining are removed while the workpieces go through each tank from (3a) to (3g) of the cleaning apparatus (3). The resulting workpieces (2) are then used in downstream processes.
However, the aforementioned cleaning apparatus of the related art is configured so that each of the tanks (3a) to (3g) are arranged at an equal distance and the workpieces (2) go through each of the tanks (3a) to (3g) held in a cleaning basket (1) for a predetermined time, therefore, the workpieces (2) still having deposited rinsing liquid are sent to the drying tank (3f); if the rinsing liquid is pure, the liquid evaporates leaving almost no spots on the workpieces (2); however, if the rinsing liquid contains impurities, the impurities generate spots on the workpieces (2) as illustrated in FIG. 4.
The workpieces (2) having such spots (5) are considered defects in a visual inspection, demanding removal of these spots. In addition, when the workpieces (2) having these spots are used as a component for a hard disk driving motor such as a magnetic disk driving system, the particles which constitute the spots (5) peel off while the motor rotates, to enter between the disk and the magnetic head, possibly triggering damage to the magnetic head or causing recording/reproducing errors.